HBase源码分析3—HMaster启动过程

by yiz96 25. 12 月 2017 hbase, 数据库 2

Main Entry

首先找一下启动的入口。从HBase的启动脚本中可以找到类似

if [ "$COMMAND" = "master" ] ; then
  CLASS='org.apache.hadoop.hbase.master.HMaster'

1 2	if [ "$COMMAND" = "master" ] ; then CLASS='org.apache.hadoop.hbase.master.HMaster'

从这里确定了入口的包 org.apache.hadoop.hbase.master ，在 HMaster 类中有 main 方法

public static void main(String[] args) {
    VersionInfo.logVersion();
    new HMasterCommandLine(HMaster.class).doMain(args);
}

public static void main(String[] args) {

VersionInfo.logVersion();

new HMasterCommandLine(HMaster.class).doMain(args);

}

HMasterCommandLine 继承自 ServerCommandLine ，doMain()执行的是基类的方法，借助 ToolRunner 执行了 HMasterCommandLine.run() 。

public void doMain(String args[]) {
    try {
        int ret = ToolRunner.run(HBaseConfiguration.create(), this, args);
        if (ret != 0) {
            System.exit(ret);
        }
    } catch (Exception e) {
        LOG.error("Failed to run", e);
        System.exit(-1);
    }
}

public void doMain(String args[]) {

try {

int ret = ToolRunner.run(HBaseConfiguration.create(), this, args);

if (ret != 0) {

System.exit(ret);

}

} catch (Exception e) {

LOG.error("Failed to run", e);

System.exit(-1);

}

public static int run(Configuration conf, Tool tool, String[] args) 
    throws Exception{
    if(conf == null) {
      conf = new Configuration();
    }
    GenericOptionsParser parser = new GenericOptionsParser(conf, args);
    //set the configuration back, so that Tool can configure itself
    tool.setConf(conf);
    
    //get the args w/o generic hadoop args
    String[] toolArgs = parser.getRemainingArgs();
    return tool.run(toolArgs);  //这里，tool是doMain中传来的this，也就是HMasterCommandLine对象
  }

public